• Animal cells and systems
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• 제3권3호
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• pp.247-252
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• 1999

The aim of this study was to characterize antipredator tactics of anurans and to evaluate the effectiveness of these tactics for predator avoidance in real confrontations. Two types of experiments were conducted. In one experiment, one predator and one prey were placed together for one hour in a small confined space (one-to-one interaction). In another experiment, one predator and several prey were placed together for one day in a large enclosure in a field (field-based interaction). The prey consisted of three anuran species, Rana nigromaculata, R. rugosa, and Bombina orientalls: a snake species, Rhabdophis tigrinus tigrinus, was used as a predator. Results of both experiments demonstrated a range in antipredator responses of the frogs, from toxicity and warning coloration, coupled with slow responses in Bombina to little (or only slight) toxicity, crypsis, and fast take-off responses to the predator in the ranids. oth ranid species exhibited lower survival(57%) than Bombina (95%) in the field-based interaction, suggesting that motor responses of the palatable prey due to attacks of the predator ultimately limited their survival. The jumping of the ranids increased the activity of the predator, which became more likely to strike. Simple crouching(seen in R. rugosa and B. orientalis) and chemical defense (in Bombina) reduced predatory attacks.

• 한국신뢰성학회지:신뢰성응용연구
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• 제18권1호
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• pp.56-65
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• 2018

Purpose: The purpose of this study is to estimate shelf life of fuze MTSQ (Mechanical Time & Super Quick) KM577A1 from Ammunition Stockpile Reliability Program (ASRP) data. Methods: For many years, ammunition test data had been gathered from ASRP. In this study, lot selection criteria and reliability score of functioning time for fuze are proposed. Reliability score of functioning time and failure data are used to estimate shelf life. Results: The results of this study are as follows; The failure modes of fuze MTSQ KM577A1 are dud, inverse function and mechanical time functioning failure (not operating in intended time). Dud and inverse function are major failure modes. Fuze MTSQ KM577A1's shelf life ($B_5$) is estimated 18.2 years conservatively. Conclusion: Degradation of chemical components in fuze MTSQ KM577A1 is major factor for its reliability. And shelf life ($B_5$) of fuze MTSQ KM577A1 is estimated 18.2 years conservatively.

• 대한안전경영과학회지
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• 제16권3호
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• pp.175-183
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• 2014

In spite of international efforts to control nuclear weapons and chemical, biological, and radiological (CBR) weapons, North Korea obtains and sells CBR weapons illegally. As a result, the worldwide threat of CBR weapons is increasing. Unfortunately, civil defense education and training for CBR weapons have not been adopted for real situations because of the long period of absence of an actual combat. In this study, virtual training scenarios that are applied to the simulation were made in 5 steps to cope with CBR situations. These scenarios are expected to have three effects. First, trainings can be improved with experience and education. Second, the problems and health hazards of CBR weapons and supplies can be solved with CBR virtual training simulation experience. Finally, corresponding effects can be recognized and predicted in real situations through roles and mission procedures of simulation scenario.

• Carbon letters
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• 제8권2호
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• pp.127-133
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• 2007

In this study, commercially available pitch-based carbon fibers of general grade were post-heat-treated using a boxtype high temperature furnace at $1800^{\circ}C$, $2000^{\circ}$, $2200^{\circ}C$, and $2400^{\circ}C$, respectively. The fundamental characteristics of each heat-treated carbon fibers were investigated in terms of chemical composition, morphology, thermal stability, X-ray diffraction, single filament tensile test, and electrical resistivity. The result showed that the fiber properties were significantly influenced by the post-heat-treatment, indicating the greater effect with increasing treatment temperature. The carbon contents, thermal stability, and tensile properties of the carbon fibers used here were further increased by the post-heat-treatment, whereas the d-spacing between graphene layers and the electrical resistivity were reduced with increasing post-heat-treatment temperature.

• 한국군사과학기술학회지
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• 제20권6호
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• pp.853-859
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• 2017

Terrorists always threats the global security with the possibility of using prohibited warfare, NBCs(Nuclear, Biological and Chemical Warfare). Compared to other prohibited warfares, most of biological warfare agents (BWAs) have no physical properties and time delays from spread to affect. Therefore the early detection is important to protect and decontaminate from BWAs. On the preliminary detection stage for suspicious material, most of detection kits only serve to know weather the BWAs exists or not. Due to this reason, simple field confirmation testing for suspicious substances have been used to identify materials which show negative result on detection kits. Considering the current Lab on a Chip(LOC) technologies, we suggest simple identification platform for unknown suspicious substances based on paper fluidics. We hope that our research will envision the future direction for the specific point-of-view for LOC technologies on detection strategy of BWAs.

• 한국군사과학기술학회지
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• 제17권2호
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• pp.282-288
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• 2014

In this research, we investigated synthetic method of 2,6-DANT that can be used as a chain extender of urethane/urea and epoxy materials in a demilitarization method via chemical transformations considering environmental, economical aspects and stability of process. We was able to identify through GC monitoring that 2,4-DANT and 2,6-DANT were produced when we inject 'hydrazine monohydrate 3.3 eq. by TNT 1 eq.' with a fine metering pump for 30 minutes and then, reflux for an additional 2 hours. We was able to isolate only 2,6-DANT(99.3% purity and 45.0% yield) from mixture of 2,4-DANT and 2,6-DANT through the separating and refining methods using 2,6-DANT solubility in methanol and crystallinity of 2,6-DANT.

• 한국추진공학회지
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• 제25권4호
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• pp.36-42
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• 2021

본 연구에서는 리오셀 섬유를 사용하여 연속식 흑연직물을 제조함에 있어, 리오셀 섬유에 phosphoric acid, ammonium phosphate, diammonium hydrogen, triammonium phosphate의 인계난연제를 처리 후 열중량, 푸리에변환적외선분광, C-핵자기공명분광, X-선 회절, 중량 분석을 통해 나타나는 물리적, 화학적 구조 변화에 대하여 고찰하였다. 인계난연제에 의한 열적 거동을 분석을 통해 내염화 공정의 온도, 가스, 처리시간 등에 대한 조건을 설정하였다. 연속식 내염화, 탄화, 흑연화 공정을 통해 인장강도 1,007.19±11.47 N/5 cm와 수율 25.3%의 흑연직물을 제조하였다.

• 드라이브 ㆍ 컨트롤
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• 제20권1호
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• pp.1-7
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• 2023

In this study, the structural stability of the tank room of an aircraft rescue fire engine is to be studied. The tank room of the aircraft rescue fire engine is filled with fire extinguishing water and chemicals. Fire extinguishing water and chemical are filled to a capacity of about 12.5 tons and are subjected to high stress. The tank room is made of PP material with low yield stress. Structural analysis of the tank room is performed and structural weakness is analyzed. In addition, if a structural problem occurs as a result of structural analysis, an analysis simulation result is presented to derive an improved design and to show the validity of the structural stability of the tank room.

• 품질경영학회지
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• 제51권4호
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• pp.735-749
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• 2023

Purpose: The purpose of this study is to derive solutions and prevent similar cases from occurring by analyzing the causes of cracks found in temperature cycling tests of rocket motor. Methods: By combining the results of the current state confirmation test, non-destructive test, domestic and foreign rocket motor comparison test, cutting test, and adhesion test according to the number of times to apply mold release agent, a Cause and Effect Diagram analysis was performed to derive the cause of cracks. Results: Through this study, 26 factors that could cause cracking in rocket motors during temperature cycling tests were identified. Through various additional test results, a total of five causes were identified, including chemical and structural design of the joint between the propellant and stress relief insert, omission of procedure in the manufacturing procedures, natural aging due to temperature, and load accumulation due to temperature changes. The fundamental cause was confirmed to be insufficient consideration of the release properties of the propellant and stress relief insert. Conclusion: During the design process, it was confirmed that this could be solved by structurally or chemically designing the insert so that it does not combine with the propellant, or by applying a mold release agent during the manufacturing process.

• 동의생리병리학회지
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• 제28권5호
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• pp.537-547
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• 2014

The object of this study was to observe the effect of Banhasasim-tang (BHSST) on the HCl/EtOH-induced gastric ulcer in mice. Three different dosages of BHSST extract (400, 200 and 100 mg/kg) were once orally administered 1 hr before HCl/EtOH mixture treatment. One hour after HCl/EtOH mixture single oral treatment, the changes on the gross hemorrhagic lesion scores, fundic histopathology, gastric nitrate/nitrite contents, lipid peroxidation and antioxidant defense system (catalase and superoxide dismutase (SOD) activities) were observed, and compared with that of ranitidine 100 mg/kg. As results of all three different dosages of BHSST extract treatment in the HCl/EtOH-induced gastric ulcer mice, significant and dose-dependent decreased gastric damages. BHSST extracts also increased gastric nitrate/nitrite contents and strengthened the antioxidant defense systems, and increased the activities of catalase and SOD, respectively. BHSST extracts 200 mg/kg showed similar anti-ulcerative effect as compared with ranitidine 100 mg/kg, in this experiment. BHSST has favorable protective effects against to the HCl/EtOH-induced gastric damages, through the strengthening of the body antioxidant defense systems. These gastroprotective effects of BHSST against HCl/EtOH-induced gastric ulcer considered as results of complicated synergic effects of their 8 kinds of herbal components, but exact synergic or individual herbal effects are difficult to discuss in this study. Therefore, more detail synergic effects between 8 kinds of individual herbal component of BHSST should be tested with screening of active anti-inflammatory chemical ingredients, in future.